This invention relates to the field of pumps, and more particularly, to industrial type pumps and related pump components. In many cases a pumping system includes an oil lubricated vacuum pump which is utilized to prime the system. Typically, the oil sump of an oil lubricated vacuum pump must be drained daily to remove water and oil emulsion. In some cases, unscrupulous pump operators do not follow the recommended procedure for disposing of this waste oil, and simply drain this waste oil onto the ground. Even when the proper draining procedure is used, these oil lubricated pumps can be a source of pollution. A fine mist of oil typically is discharged from the oil lubricated vacuum pump. An oil trap may be installed on the oil lubricated vacuum pump in an attempt to reclaim this oil. Even when an oil trap is utilized, however, oil sometimes escapes. The oil lost by an oil lubricated vacuum pump can be one to two cups a day, or 15 quarts per month. This oil is discharged either on the ground as liquid or into the air as a fine mist, both of which are undesirable.
For many applications, the fluid being pumped includes suspended solids such as and, silt, rocks, rags etc. In these applications a strainer is often coupled to a distal end of the inlet hose to prevent large solids from being drawn into the pump. Suction created at the distal end of the hose during a pumping operation may draw an accumulation of foreign material up against the strainer, causing the strainer to become clogged. When this occurs, a back flushing procedure may be utilized to un-clog the strainer. In a typical back flushing procedure, the head pressure created by the distance between the distal end of the inlet hose and the pump is used to create a reverse flow through the strainer. In some applications, the pump is not a great deal higher than the distal end of the inlet hose. Thus, there is very little head pressure available for a back flushing procedure. Even in cases in which the pump is a good distance higher than the distal end of the inlet hose, the head pressure is sometimes not adequate to unclog the strainer.